Malicious search results are a constant problem for search engines, and Google is a whole lot better at filtering them out than Bing.

So says a report from German research firm AV-Test (PDF), which found that Bing served up five times as many malicious sites in search results than Google did over an 18-month period. Out of the 10 million search results delivered by both sites, Google served up 272 potentially nasty sites and Bing returned 1,285.

The situation is somewhat funny given Microsoft’s constant attacks on Google’s search results. But while there’s a lot of room for debate on that topic, it’s tough to argue with the numbers from the AV-Test report: Right now, Google is doing a better job at search than Microsoft is.

But while Bing still has room for improvement, it’s doing a far better job than Russian search site Yandex, which AV-Test says delivered 3,300 bad sites — twice as many as Microsoft’s search engine.

Yandex, understandably, isn’t particularly happy with the report and has many questions about how it the study was performed.

“Yandex uses its own proprietary antivirus technology to protect users from malicious software. Yandex marks the infected webpages in its search results in order to notify users of unsafe content. We just notify users of possible consequences and do not block access to the webpage completely,” the company said in a statement to VentureBeat.

In all, the report shows what should already be clear: The more sites search engines index, the more they have to worry about bad results. And no one has figured out a perfect way to drop that malware number to zero.